The conventional technique for measuring thickness of an object is commonly applied by using a measuring device that includes a fixed body and a flexible component connecting with an electro optic system. The flexible component is capable of being stretched or compressed relatively to the fixed body. While the flexible component has been touching the object, a displacement of the flexible component relative to the fixed body is detected by the electro optic system, so the thickness of the object is obtained.
However, the technique applying the electro optic system is very complicated, and the purchase cost and the maintenance cost for the measuring device is also very expensive. Moreover when more than one measuring device is required while a plural objects are measured at the same time, the cost become remarkable.